Flexiblity tester



June 2l, 1949. M L. ANDERSON 2,473,841

FLEXIBILITY TESTER Filed June 6, 1946 2 Sheets-Sheet 1 4%4 PM2/ f f@ 34 a 24 27 /M/E/vro/r 26 27C AMM/ rz Maf/fsm June 21, 1949. M. ANDERSON FLEXIBILITY TESTER 2 Sheets-Sheet 2 Filed June 6, 1946 17504/ ywl. l

Patented June 2l, 1949 FLEXIBILITY TESTER Maurits L. Anderson,

Arlington, Mass., asslgnor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application June c, 1946, serial No. 674,145

(ci. 'z3- 100) 2 Claims.

l This invention is directed to apparatus for testing the exibility of materials subjected to strain induced by bending and is more particularly directed to the testing of heater coatings of a hard ceramic nature.

Previous methods employed for testing the ilexibility of materials used for coating heater wire were conducted along lines based on trial and error. The coated heater wire under test was exed by hand until the coating broke. If the coating broke down at an unsatisfactory bending angle the exact value of which was a very wide guess, a new coating was tried. This method proved very unsatlsfactory'as it was impossible to establish a deiinite reference point to which the :dexibility of other coatings could be compared.

It is, therefore, an object of the present invention to provide a device which will establish the breaking point based on the angle ofrotation through which the tested material is bent.

The above object and others will become more evident as vthe description of the present invention progresses and is illustrated by the attached drawings in which:

Fig. 1 is a plan view of the device of the presy ent invention;

Fig. 2 is a cross-sectional view along line 2-2 of Fig. 1;

. Fig. 3 is a partial view oi the device of the present invention depicting the operation of said device;

Fig. i is a cross-sectional view along line 4-5 of Fig. 1; and

Fig. 5 is a cross-sectional view along line 5 5 of Fig. 1.

Referring now more particularly to Fig. 1, a flat member i0, which be constructed of plywood, Masonite, Bakelite or the like, serves as a support for a scale il, said scale being attached to member I@ by screws i2, or said scale may be inscribed directly on the surface of member iii. Also attached to said member i is a clamping mechanism comprising a pair of clamping jaws, jaw I3 being immovably attached to member IIJ and jaw i4 being movable, said movable Jaw when withdrawn from contact with jaw I3 allowing the insertion of the coated wire 25 between said jaws i3 and i4. Fixed jaw I3 is integral with and perpendicular to its supporting member I5. An elongated member i6 is firmly attached to Jaw i4 for manually withdrawing said jaw from contact with Jaw I3. Said member i6 is maintained in proper alignment by a pair of guide members i1 and Il. Integral with said last-named members l1 and I8 are portions I9 and 20 perpendicular to said members and I8, said portions I 9` and 20 having apertures through which the member |6 passes with a slidable lt. Surrounding member I6 is a resilient member 23, which may .be a helical spring disposed between Vertical portion 20 and movable jaw I4 for urging said jaw into rm contact with jaw I3. Said resilient member 23 should have sufiicient tension to rmly hold the coated wire 25 in place.

Also attached to member I0 is a disk member 24 for supporting a pivotal member 26. The configuration of member 2t Was arbitrarily selected in this particular embodiment and can therefore be formed in any manner desired. Further, a1- though the present embodiment indicates a supported pivotal member, said member can be made integral with its support, for example, by turning such a combination from a single piece of material.

Rotatably attached to the pivotal member 26 is an indicating pointer 21 having an inscribed line 28 on its upper surface, said line extending to the unattached end of member 2l and being radially disposed with respect to scale I I. Pointer 2l is rounded at the pivotal end 21A thereof and the lower edge of said pointer 21 extends from a point 21B on said rounded edgeA 21A so that the width of said pointer between 21B and 21C is such that it will allow substantial rotation of same.

Integral with member 2l and perpendicular to the plane surface thereof is portion 29, said -portion being the fixed jaw of a second clamping assembly, the movable jaw 30 of said last-named assembly being maintained in juxtaposition to said fixed jaw 29 by threaded member 3|. Jaw 30 is under tension by reason of the pressure exerted upon it by resilient member 29A, said member 29A surrounding member 3| and being disposed between the jaws 29 and 30. Said member 3| passes through, With a slidable t, an aperture (not shown) in movable jaw 30 and thread-` edly engages with xed jaw 29. Rotation of threaded member 3| urges movable jaw 30 into iirm contact with xed jaw 29 for firmly holding in place the other portion of coated wire 25A.

Fig. 2 illustrates a partial cross-section along line 2-2 of Fig. 1 of the device to show in detail means for momentarily restraining the motion of pointer 2l. The pointer actuating knob 32 in this particular embodiment has an extended portion 33 which engages an indent 34 in scale Il. Said extended portion 33 is held in engagement with indent 24 by the combination of washer Il and resilient member position on extended portion 29 in a circumferential groove (not shown) thereon, the washer being forced into said groove (not shown) after the resiilent member is placed in position. Resilient member 35 exerts sumcient pressure against the washer. by reason of its disposal between said washer 99 and the underside of pointer 21, to urge said extended portion 92 into engagement with indent 24. Very little force is required to disengage the pointer from its position. Indent 24 is used to hold the pointer 21 in position while inserting the coated wire sample between the clamping jaws 29 and 20.

The operation of the device is clearly illustrated in Fig. 3, the broken of pointer 21 before it is actuated and the full line illustration of pointer 21, after being rotated in a clockwise direction through a length of arc from zero position 39, showing, how the coated wire 25 is formed into a loop. Actuatlon of pointer 21 is continued in the direction above indicated until the coating on looped wire 2l breaks. At

this point, note is made of the number of degrees through which said pointer was rotated and this figure represents a relative value of the flexibility of the coating on coated wire 2l. Although the scale il in this particular embodiment was inscribed in degrees of angular rotation, any other form of indicia may be used.

The distance between clamps I9, I4 and 29, 99 when same are in linear relation with each other and the zero reference point 29 is sufilcient to allow the greatest amount of rotation of pointer 21 without interference by clamping sumuort Il but does not exceed a distance which would inhibit the formation of a small enough loop to properly establish the flexibility of the coating on coated wire 25.

Fig. 4 illustrates more clearly in cross-section the fixed clamping means i9 and Il and the manner in which said clamping means are operated. These means provide rapid insertion or removal of the sample 25 undergoing the test by manipulation of member i6.

4In Fig. 5 is illustrated in cross-section the arrangement of clamping jaws 29 and Il. Here the force urging jaws 29 and 30 together is a threaded member 3| and a resilient member 29A; for example, a helical spring surrounding said member 3i maintains jaws 29 and 30 in open position to permit the ready insertion of the coated wire end 25A between said jaws before they are clamped together. The arrangement described in connection with Fig. 4 can be readily adapted to the clamping means described in this paragraph without interfering with the actuation of the pointer 21, or a cam arrangement bearing against jaw 30 can be utilized instead of threaded member Il.

While what has been described hereinbefore is one embodiment of the present invention, said device may be adapted to the testing of other types of material; for example, it may be desirable to test the flexibility of corrugated pipe or ilexible shafting to determine the maximum allowable curvature of said material or perhaps to test the ilexibility of plastic material. In the aforementioned example it would only be necessary to make 2l. The washer 99 is held in` lines 21 showing the position' the device of the present invention of heavier materials. It should be understood, therefore, that many modiilcations may be made without departing from the true spirit and scope of the present invention.

What is claimed is:

1. Apparatus for testing the ilexibility of flexible linear members, comprising supporting means having attached thereto an arcuate scale, a pivot pin mounted on said supporting means at the center of the arc of said scale, a pointer mounted for rotation on said pin and radially positioned with respect to said scale, means supported on said pointer for clamping the member to be tested, and a second clamping means relatively ilxed with respect to said first clamping means and spaced therefrom, said pointer having a zero reference position in which the clamping surfaces of said clamping means are disposed linearly with respect to each other. said clamping surfaces being located on opposite' sides of said pin when said pointer is in said reference position, whereby the member to be tested may be clamped between said two clamping means and whereby when said pointer is rotated from said zero position a loop is formed in the tested member between said two clamping means.

2. Apparatus for testing the flexibility of flexible linear members, comprising substantially horizontal planar supporting means having attached thereto a substantially horizontal planar arcuate scale, a vertical pivot pin mounted on said supporting means at the center of the arc of said scale, a pointer mounted for rotation on said pin in a horizontal plane and radially positioned with respect to said scale, means ysupported on said pointer for clamping the member to be tested. and a second clamping means fixedly attached to said supporting means and spaced from said first clamping means, said pointer having a zero reference position in which the clamping surfaces of said clamping means are disposed linearly with respect to each other and in substantially vertical planes, said clamping surfaces being located on opposite sides of said pin when said pointer is in said reference position, whereby the member to be tested may be clamped substantially horizontally between said two clamping means and whereby when said pointer is rotated from said zero position a loop is formed in the tested member between said two clamping means.

MAURITZ L. ANDERSON.

REFERENCES CITED The following referenices are of record in the ille of this patent:

UNITED STATES PATENTS Great Britain Aug. 25, 1927 

